Nutrient release and flux dynamics of CO₂, CH₄, and N₂O in a coastal peatland driven by actively induced rewetting with brackish water from the Baltic Sea

Abstract. The rewetting of drained peatlands supports long-term nutrient removal in addition to reducing emissions carbon dioxide (CO2) and nitrous oxide (N2O). However, may lead short-term leaching into adjacent water high methane (CH4) emissions. consequences with brackish on greenhouse gas (GHG) fluxes remain unclear, although beneficial effects such as lower CH4 seem likely. Therefore, we studied the actively induced a coastal peatland water, by comparing pre- post-rewetting data from bay. Both potential transport nutrients shift GHG (CO2, CH4, N2O) accompanying change inundated conditions were analyzed based measurements surface concentrations (dissolved inorganic nitrogen, DIN, phosphate, PO43-), oxygen (O2), components CO2 system, N2O together manual closed-chamber fluxes. Our results revealed higher rewetted than bay, indicating that leached out peat exported A comparison DIN bay those an unaffected reference station showed significant increase after rewetting. maximum estimated export (mean ± 95 % confidence level) was calculated be 33.8 9.6 t yr?1 for DIN-N 0.24 0.29 PO4-P, depending endmember (bay vs. station). also source first year spatial temporal variability decreased, emissions, reported freshwater rewetting, did not occur. SD) decreased slightly 0.82 g m?2 h?1 (pre-rewetting) 0.26 (post-rewetting). availability organic matter (OM) dissolved likely most important drivers continued production. Pre-rewetting ranged 0.13 1.01 mg (drained land site) 11.4 37.5 (ditch). After formerly dry increased 1 order magnitude (1.74 7.59 h?1), whereas former ditch 8.5 26.9 h?1. These comparatively low can attributed suppression methanogenesis oxidation available O2 sulfate peatland, which serve alternative electron acceptors. flux low, annual mean 0.02 0.07 suggest could account high, currently unmonitored, inputs at least short timescale few years. decrease might favored over reduce